1. Technical Field of the Invention
The invention of the Application relates to a manufacture technology of so-called xe2x80x9cnon-washing ricexe2x80x9d dispensing from rice washing before cooking, that can be cooked only by adding water, and moreover, presenting a long shelf life, and more particularly, to a manufacturing method of non-washing rice for washing rice under the rice washing conditions appropriate for the polished rice to be used and an apparatus thereof.
2. Related Art
If the polished rice is washed with water by an ordinary method, water penetrates into the polished rice increasing the moisture content, provoking easily mold or putrefaction, and it can not become a non-washing rice that can be treated similarly to the ordinary polished rice. Howsoever, if a polished rice once presented a high moisture content by washing with water is dried, as the starch layer of the polished rice has a characteristic to swell upon water absorption and to shrink upon drying (refer to Japan Patent Publication HEI 3-36496), only the surface layer of the polished rice shrinks suddenly upon drying, a tensile force acts on the surface section, generating cracking. It is well known that, upon cooking, the polished rice presenting cracking swells unevenly due to infiltration of a quantity of water through the cracking, or a quantity of starch grains, resulting in a rise extremely bad in consistency and taste.
Therefore, technologies for obtaining a non-washing rice easy to conserve, and presenting a good taste, by washing within an extremely short time before almost no water infiltrates inside the polished rice, and removing immediately water adhered to the surface of the polished rice is proposed in the Japan Patent Application. Laid-Open Publication HEI 2-242647 and the Japan Patent Application. Laid-Open Publication HEI 3-154643. These technologies can manufacture theoretically a non-washing rice free from cracking, as they do no dry a polished rice once presented a high moisture content to reduce the moisture content.
However, depending on the washing water temperature, or the nature of raw material of polished rice, it is difficult to wash the polished rice and remove water adhered to the surface, within such a short time that the water infiltrating the polished rice remains within around 1 weight % of the polished rice, by applying publicly known rice washing apparatuses or dehydrating (evaporation drying) apparatuses.
For, when polished rice is cooked without washing, rice smells bran, rice becomes yellow, or rice become crumbling without consistency, mainly because a semi-liquid mixture (called ariulone residue) presenting an extremely high viscosity composed of oils, greases, proteins, or carbohydrates contained in the ariulone layer (starch layer) which is the lowest layer of the bran layer of the brown rice, adheres to the surface of the polished rice (refer to the Japan Patent Application. Laid-Open Publication HEI 3-154643), and it is necessary to remove this ariulone residue almost completely. By the way, ariulone residue is difficult to isolate from the polished rice only by floating the polished rice in water, because of its high viscosity, and it is necessary to soak the polished rice in the water and rub the surface of the polished rice to isolate. However, the polished rice reduces in strength upon water absorption, and especially, the cell structure of the surface becomes vulnerable, and the damage thereof will affect badly the taste similarly as cracking, so it is a taboo to apply a strong friction force to the surface of the polished rice.
Consequently, the conventional rice washing apparatus is composed, independent of the method thereof (there are methods for rotating an agitation wings in a washing tube and agitating water and polished rice, for inputting water and polished rice in a washing tube where an impeller is fixed inside and rotating the washing tube per se, for agitating water and polished rice transporting the polished rice by a screw conveyer, for jetting a strong water flow or air flow to the polished rice in the water for agitation, or other methods), to weaken the friction force applied to the polished rice not to damage the polished rice in any method, but to assure a sufficient washing by taking, in place thereof, a relatively long time for washing. Consequently, it is substantially impossible to remove ariulone residue almost completely, within a short time appropriate for the non-washing rice manufacture, using such a rice washing apparatus.
In addition, as for the removal of adhered water also, centrifugal dehydrater or net conveyer (evaporate adhered water by wind) or others may be conceived as publicly known apparatus; however, only by dehydrating with a centrifugal dehydrater, it takes time for further dehydration from the time point when the adhered water became about 3 weight % or less of the polished rice, and an excessive filtration of adhered water into the inside of the polished rice generates.
On the other hand, for the net conveyer, it is difficult to make the wind come into contact evenly with all over the surface of the polished rice, and there is every chance that a part of grains of the polished rice, or, a part of area of a grain of polished rice is dried excessively, causing a so-called irregular drying, and provoking the cracking. It might be proposed to evaporate by rolling the polished rice in order to prevent this, however, this will damage the structure of the polished rice surface layer softened by water absorption.
From the foregoing, it can not be said that an apparatus executable for washing the polished rice and removing the adhered water is disclosed in the Japan Patent Application. Laid-Open Publication HEI 2-242647, and, in the non-washing rice manufacture apparatus disclosed in the Japan Patent Application. Laid-Open Publication HEI 3-154643, is believed to be capable of manufacturing anyhow a non-washing rice, it should be improved further, in order to manufacture a high quality non-washing rice independently of washing water temperature, relative humidity of the atmosphere, or other conditions.
Therefore, the inventor of this Application, has previously invented a novel non-washing rice manufacture apparatus, and this non-washing rice manufacture apparatus is registered as the U.S. Pat. No. 2,141,449.
This patented invention has made possible to perform the processing from washing to evaporation for the polished rice within a short period of time and, moreover, to manufacture actually a non-washing rice dispensing from rice washing before cooking, and presenting an excellent taste and a long shelf life.
By the way, the nature of the polished rice used for manufacturing the non-washing rice varies according to the rice quality, kind, moisture content, polishing degree, age after the harvest, or others, and they don""t have all the same nature. Consequently, it is necessary to adjust the washing intensity according to the conditions that the polished rice presents.
However, in the aforementioned conventional technology, no measure is taken for controlling the washing step according to the nature of the polished rice. In the course of improvement study of said non-washing rice manufacture apparatus, the inventor of the present invention has remarked that a polished rice having a better taste can be manufactured, by controlling the washing condition according to the conditions of the polished rice.
The present invention intends to solve the aforementioned conventional problems, by a non-washing rice manufacture apparatus, comprising:
a pressure rice washing means for washing polished rice through intermediate of water and air, a rinsing dehydrating means for removing water adhered to the polished rice passed through the pressure rice washing process, a moisture adjustment means for drying polished rice passed through rinsing dehydrating to adjust the moisture content thereof to a predetermined value, and a rice washing intensity adjustment means for controlling as desired the intensity of rice washing in the pressure rice washing process according to the conditions that the polished rice presents; wherein:
said pressure rice washing means has a plurality of water injection means for supplying polished rice with washing water, and an agitation roll provided with a helical projecting rib on the peripheral surface is disposed rotationally drivable in an agitation tube having an inlet of polished rice at one end and an outlet at the other end;
said rinsing dehydrating means is formed by disposing in a rotationally drivable manner a centrifugal dehydrating tube provided with a porous peripheral wall, disposing a screw tube inside the centrifugal dehydrating tube coaxially with the centrifugal dehydrating tube and differentially and rotationally drivable with the centrifugal dehydrating tube, pushing a rice supply pipe for supplying in the screw tube with polished rice from the pressure rice washing means through the screw tube, and providing a rice discharge port for discharging polished rice supplied from a rice supply pipe toward the peripheral wall of the centrifugal dehydrating tube, a screw blade for moving axially polished rice discharged from the rice discharge port along the peripheral wall of the centrifugal dehydrating tube, and a rinse water discharge port for discharging rinse water toward the polished rice moved by the screw blade;
said moisture adjustment means comprises a net disposed rotationally drivable for deploying polished rice from the rinsing dehydrating means over the top face thereof, and a suction blower for sucking air from under the net; and the rice washing intensity adjustment means is composed of a rice washing pressure adjustment means for controlling as desired the pressure to the polished rice in said pressure rice washing means.
In said composition, the rice washing intensity adjustment means may be composed of a pressure rice washing means whose inclination angle in the axial direction of the agitation tube can be set as will, an angle adjustment means for setting said pressure rice washing means to a desired inclination angle, and a rotation speed adjustment means of the agitation roll.
In any one of said compositions, the helical projecting rib formed on the peripheral surface of the agitation roll may comprises a polished rice feed section, a rice washing section and a polished rice carrying-out section, the pitch of the helical projecting rib of said respective section being smaller in the feed section than that in the rice washing section, and larger in the carrying-out section than that in the rice washing section, and a drain section having a number of small holes may be provided at points corresponding to said rice washing section and carrying-out section on the peripheral surface of the agitation tube.
Further, in any one of said compositions, a draft may be disposed upper than the rinse water discharge port of the screw tube peripheral wall, and a wind generating blade rotating integrally with the centrifugal dehydrating tube is disposed outside the centrifugal dehydrating tube peripheral wall.
Moreover, in any one of the aforementioned compositions, a draft may be disposed upper than the rinse water discharge port of the screw tube peripheral wall, the surrounding of the centrifugal dehydrating tube is covered with a casing having a exhaust drain port, and a suction blower is communicated with the exhaust drain port.
Further, in any one of the aforementioned compositions, the rotation speed of the net of an evaporation means may be adjustable.
Besides, in any one of the aforementioned compositions, respective processing means may be connected so that the polished rice inlet of a processing means of the following process side is positioned under the polished rice outlet of a processing means of the previous process side, thereby allowing the polished rice to pass sequentially respective processing means, without providing a transport means between respective processing means.
And further, in any one of the aforementioned compositions, a driving control means for controlling the operation of pressure rice washing means, rinsing dehydrating means, moisture adjustment means and rice washing intensity adjustment means may be provided so that the operation of said respective means is executed based on data concerning the polished rice input to the control means.
And, in any one of said compositions, a rice washing intensity adjustment means may comprise a rice washing pressure adjustment means and a washing water flow adjustment means in said rice washing means.
Besides, the present invention provides a non-washing rice manufacture method, comprising steps of:
washing polished rice in an agitation tube having therein an agitation roll, disposed rotationally drivable, provided with a projecting rib on the peripheral surface rinsing the polished rice passed through the rise washing process to dehydrating attached moisture, and next, drying the polished rice to set the moisture content to a predetermined value, wherein:
said step of washing polished rice comprises a feed step for transporting the polished rice from the inlet of the agitation tube to the inside, a polishing step for washing the polished rice and a rough rinsing step washing with water the polished rice from the polishing step and, at the same time, said polished rice washing step is so composed to wash the rice by adjusting the rise washing pressure, the rotation speed of the agitation roll and the washing water supply amount, according conditions presented by the polished rice.
In addition, said manufacture method may be composed to adjust the rise washing pressure, the rotation speed of the agitation roll and the washing water supply amount based on the data concerning the polished rice input to said control means.